1. Field of the Invention
The present invention relates to equipment for pipe strings such as drill pipe strings comprising a side entry sub for passing the cable from the inside to the outside of the pipes, with hydraulic sealing about the cable.
2. Description of the Prior Art
Side entry subs are well known by oil drilling specialists, such a device is described for example in the British patent No. 2 135 719.
A side entry sub is for example used in the technique described in the French patent Nos. 2 501 777 and its first two additions FR-A-No. 2 522 059 and 2 564 893, the patents FR-A-No. 2 502 236, U.S. Pat. Nos. 4,603,578, 4,607,693 or 4,070,239.
According to this technique, for carrying out well logging or work operations in horizontal or highly slanted wells, a well logging probe (or a work tool) is initially fixed to the lower part of a pipe string which is lowered into the well as it is formed.
Then, inside the pipes, an electric cable is lowered (by gravity and pumping) having a weighted connector (the connector may comprise a load bar mounted thereover) which connects with a complementary connector fixed to the top of the probe or tool. In the portion of the pipe string corresponding to the vertical or slightly slanted portion of the well, a side entry sub provides passage of the cable from the inside to the outside of the pipes.
Recording of the measurement (or the work in the well) is executed by displacing the of the entire length of the pipe string from the surface.